In one method for spark-erosive wire cutting operations, known as wire-erosion, a contour is cut into, or from, a second electrode—the workpiece—beginning from a starting hole or a reference surface using a first electrode—the erosion wire or the wire electrode. The wire electrode is continuously drawn from a supply coil, taken over a wire guide located above the workpiece to the processing zone and taken away through the processing zone and over a wire guide located below the workpiece. Known methods for spark-erosive wire cutting operations need to be further rationalized and simplified. The machine operator can no longer be expected to separate and thread the wire electrode manually at the start of each new cutting contour or following an unintentional wire break. An undetected wire break can also result in intolerably long machine downtimes and consequently to material losses.
Manually threading the wire electrode into closed wire guides, known as circular guides, with little play in the guide, places great demands on the operator and should therefore be automated.